Source code for cmx.with_hack

import sys




class SkipException(Exception):
    pass





class SkipContextManager:
    def __init__(self, skip):
        """
        :param skip: bool, skip code execution if True.
        """
        self.skip = skip

    def __enter__(self):
        if self.skip:
            sys.settrace(lambda *args, **keys: None)
            frame = sys._getframe(1)
            frame.f_trace = self.trace



    def trace(self, frame, event, arg):
        raise SkipException()


    def __exit__(self, type, value, traceback):
        if type is None:
            return  # No exception
        if issubclass(type, SkipException):
            return True  # Suppress special SkipWithBlock exception



if __name__ == "__main__":
    with SkipContextManager(skip=True) as this_works:
        print("In the with block")  # Won't be called
    print("Out of the with block")